Figure 1.

Joint estimation of lung PET/CT target/disease volume. (A) A fused PET/CT displayed in CERR with manual contouring shown of the subject’s right gross tumor volume. The contouring was performed separately for CT (in orange), PET (in green), and fused PET/CT (in red) images; (B) the MVLS algorithm was initialized with a circle (in white) of 9.8 mm diameter, evolved contour is steps of 10 iterations (in black), and the final estimated contour (in thick red). The algorithm converged in 120 iterations in few seconds. The PET/CT ratio weighting was selected as 1:1.65; (C) MVLS results is shown along with manual contour results on the fused PET/CT. Note the agreement of the fused PET/CT manual contour and MVLS (dice =0.87); (D) MVLS contour superimposed on CT (top) and PET (bottom) separately. PET, positron emission tomography; CT, computed tomography; CERR, computational environment for radiotherapy research; MVLS, multivalued level set.